This invention relates to dc-dc converters and more particularly to a dc-dc converter which employ a current fed series resonant circuit.
A dc-dc converter is needed which can step up the input voltage with high efficiency while operating at high frequency (to reduce magnetic component size and capacitor size). As efficiency of conversion is increased, less power need be supplied from the source to the load.
In U.S. Pat. No. 4,143,414 a series resonant converter is described that is used in a three phase silicon controlled rectifier ac-dc converter application. The rectifier and load in the circuit are connected in series with the resonant circuit. Voltage step-up cannot be conveniently be obtained and high frequency operation is also difficult to obtain using silicon controlled rectifiers. In addition, high turn-on switching losses occur since the resonant load must be run at a leading power factor to commutate the silicon controlled rectifier.
It is an object of the present invention to provide a dc-dc converter for operation at high frequencies to reduce reactive component size.
It is a further object of the present invention to provide a dc-dc converter capable of operating with high efficiencies by reducing switching losses.
It is a still further object of the present invention to provide a dc-dc converter capable of operating in a step-up mode.